Conversion of paraffinic hydrocarbons



May 25, 1943. P. OSTERGAARD CONVERSION OF PARAFFINIC HYDROGARBONS Filed Oct. 5, 1941 2 Sheets-Sheet 1 mzmhamomh m Wm w A m G May 25, 1943. P. OSTERGAARD CONVER SiON OF PARAFFINIC HYDROCARBONS Filed Oct. 5. 1941 2 Sheets-Sheet 2 s W R A A 6 mm W mr w a P m -Qv Patented May 25, 1943 um'rso sTArEs PATENT oar-ice HYDBOCARBO Povl Ostergaard. Mount Lebanon, Pa, assignor to Gulf Oil Corporation. Pittsburgh, Pm, a corporation of Pennsylvania Application October 3, 1941, Serial No. 413,510 14 Claims. (01. zed-sass) constitut high octane number gasoline boiling range fuels, likewise by contact with aluminum halide catalysts under suitable conditions. For example, normal butane, when contacted with aluminum chloride or aluminum bromide at an elevated temperature, undergoes conversion to isobutane, and when a large molecular excess of isobutane is contacted with ethylene or other lower olefin at normal or slightly elevated temperatures in the presence of aluminum chloride or aluminum bromide, the isobutane combines with ethylene or other olefin to produce a mixture of higher isoparamnic hydrocarbons boiling within the gasoline boiling point range and having a high octane number.

Nevertheless there are certain difllculties in the use of the solid aluminum halides as catalysts for the isomerization and alkylation of ,parafllnic hydrocarbons and such us -is susceptible to improvement.

In the copending application Serial No. 408,242 of Leslie U. Franklin, Marshall Elliott and William S. Bonneil, filed August 25, 1941, there is described and claimed an improved method of isoth aforesaid applications, as well as other liquid aluminum halide-hydrocarbon catalysts with which this invention is concerned, are substantially immiscible with liquid petroleum hydro carbons, including the products or paraiiin isomerization and alkylation.

merizing and alkylating parafllnic hydrocarbons wherein the hydrocarbon reactant material is contacted with a liquid aluminum halide catalyst comprising a stable dispersion of an aluminumhalide catalyst in a liquid product of alkylating a paraflin with an olefin. By this means, certain diiilculties in the isomerizatlon and alkylation of parailinic hydrocarbons in the presence of aluminum halides are obviated.

Another improvement in paraffin isomerization and alkylation is described and claimed in the copending application Serial No. 408,270, of William W. Weinrich, Louis H. Huth and Clark A. Holloway, Jr., filed August 25, 1941, such improvement comprising contacting the hydrocarbon reactant material with a liquid aluminum halide catalyst comprising a stable dispersion of an aluminum halide catalyst in a liquid or low melting solid natural petroleum oil fraction which contains not more than about 25 per cent of total aromatics. Examples of suitable petroleum oil fractions are straight run Pennsylvania kerosene and straight run Pennsylvania gas oil.

I have found, however, that the use of liquid aluminum halide-hydrocarbon catalysts of the type described and claimed inthe above-identified applications, as well as the use of other liquid aluminum halide-hydrocarbon catalysts, for the liquid phase isomerization and alhlation of paramnic hydrocarbons can be greatly improved.

I have found that in employing liquid aluminum halide-hydrocarbon catalysts, such as aluminum chloride-alkylate bottoms or aluminum chloride-Pennsylvania kerosene catalysts, for the liquid phase isomerization and alkylation' of parafllnic hydrocarbons, it is necessary, in order to obtain the greatest possible rate of reaction, not only to employ a continuous process wherein catalyst and hydrocarbon reactant material are continuously contacted. reaction prodnot and catalyst are separated from the result ing mixture, and the separated catalyst is recycled, but it is also important to contact the hydrocarbon reactant material with the catalyst so thoroughly and intimately that an emulsion or near-emulsion is produced with substantially no tendency to separate in the reaction zone and which is slow to separate by gravity separation even after removal from the reaction zone. I have further found that, under such conditions, the problem of separating catalyst from reaction product by prior methods of operation becomes so difllcult at high rates of flow that by ordinary methods of separation, separating vessels of uneconomically large size used.

I have now found, however, that such diflicuitly separable mixtures of catalyst and hydrocarbon reaction product produced in high speed mixing apparatus or the like can be readily separated, for example, by gravity, into an upper hydrocarbon layer substantially free from catalyst and constituting the major art of the reaction prodnot, and a-lower layer oi catalyst containing a Catalysts of the type descried and claimed in 5 substantial amount of reaction product, and-that by first efiecting such a partial separation, recycling part, advantageously the major part, of the separated catalyst containing reaction product to th reaction zone. and eflfecting a substantially complete separation, for example by gravity, of the unrecycled portion of said separated catalyst into catalyst and hydrocarbon reaction or number, must be separation ,ofcatalyst from reaction product'in two steps, as described, is that the necessity of uneconomically large or numerous separating vessels is obviated. v

A further and related-object achieved by this invention is a means of maintaining-[a constant amount of active aluminum halide-hydrocarbon catalyst in the system. as much as possible with-' out recourse" to materials obtained from outside the process. This object is: achievedas follows:

In theisomerizatlon of a paramnic hydrocarbon a certain amount of cracking normally oc-' curs which results in the formation of higher as wellias lower hydlmiarbons. For example, in'

the isomerization, of n-butane to iso-butane, a pentane fraction is obtainable. on fractionally distilling the reaction product,-such fraction being mainly iso-pentane. Similarly, in the alkylation of a paramn with an olefin, side reactions result in the formation of high boiling and low boiling ends which are largely iso-parafllnic. For example, in the alkylation of iso-but'ane with the butylenes,.a certain amountof Ca and higher iso-paraillns are formed, as well as Ca, C1, and lower iso-parailins. Although the; iso-pentane produced as a byproduct in the isomerization of n-butane, and the Ca and higher isoparaflins produced as byproducts in the 'alkylation of paraflins with oleilns, have a certain fuel value, they are nevertheless somewhat of the nature of waste products, being less useful and valuable than the primary reaction products.

I effectively utilize part -or.all of such high boiling ends of isomerization and alkylation reactions by'heating' and mixing them with an aluminum halide, advantageously at a temperaturebetween about 150 and 250 F. and for .a time and in amounts suflicient to produce a liquid catalyst containing not less than about 50 per cent by weight of aluminum halide stably dispersed therein, as described in the aforesaid copending applications, and I introduce the catalyst thus produced, with such further quantities of a like catalyst derived from some other source as may be necessary, into the reaction system and remove from the system a corresponding amount of catalyst which has been substantially completely separated from reaction product. The amount of fresh catalyst introduced and the amount of used catalyst removed is such that the desired amount of active catalyst is maintained in the system.

In a particularly advantageous embodiment of this feature of the invention, 1 so regulate the conditions of reaction and the fractionation of the reaction product that a suilicient amount of high boiling iso-parafllnic ends is produced to supply the iso-parafllnic hydrocarbon necessary for producing fresh catalyst. This may be done, for example, by the use of temperatures sufllciently high or times of contact sufllciently long to produce the necessary high boiling ends.

A still further and related object achieved by my invention comprises a careful regulation of the temperature and pressure of the reactants whereby they are maintainedat substantially constant temperature and pressure in the reaction zone. I accomplish this object of the invention by the use of heating or refrigerant means,

whereby the reactants are kept heated to a constant reaction temperature or heat of reaction is absorbed asrapidly as formed, and by the use of pressure regulating devices. whereby a'constant reaction pressure is maintained. Advantageously, I introduce the reactants or reactant into the reaction zone under pressure and maintain, by suitable pressure regulating valves, a

controlled back pressure on the lines and apparatus serving to remove the reaction mixture,

' thereby maintaining constant pressure in the reaction zone. a

I have found that substantial constancy of temperature and pressure in the reaction zone are very important; without such, the yields of desired product are lower and in general the processes of isomerization and alkylation in the presence of aluminum'halide catalysts are exceedingly difflcult to control in large, continuousprocess installationsand-the results obtained are erratic, By observing constancy of temperature and pressure, however, I am able to obtain very uniform and good results.

Myinvention may be further illustrated and better understood by reference to the two diagrammatic drawings which accompany and form a part of this specification.

Referring to Fig. 1, liquid normal butane stored in storage vessel l is pumped through a line 2 and a heat exchanger 3 by a pump 4 into a reaction vessel 5. Heat exchanger 3 is so operated, by the use of a hot or a cold fluid, that the liquid normal butane is brought to the desired reaction temperature before it enters reaction vessel 5. Reaction vessel 5- is advantageously provided with means to produce violent agitation and thorough intermingling of the reactants and it is provided with means for maintaining the reaction mixture at a constant temperature.

Minor amounts of HCl are introduced through a line 6 into line 2 and thus into reaction vessel 5. A liquid aluminum chloride-hydrocarbon catalyst, part of which is recycled catalyst and part of which is prepared as described below, is

- introduced into reaction vessel 5 through a line i and the catalyst, liquid n-butane and HCl are intimately contacted with each other in reaction vessel 5 at a suitable constant reaction temperature and under a constant pressure sufllcient to maintain the butanes in liquid state, thereby causing rapid isomerization of n-butane to isobutane. maintained constant by continuously removin any heat liberated by the reaction, or by supplying heat if necessary. Heating or cooling coils may be used for this purpose. A mixture of catalyst and reaction product, including unconverted n-butane and H0], is withdrawn from reaction vessel 5 through a line 8 and introduced into a separating vessel III which is provided with a cone-shaped bottom II. In separator ill the mixture is allowed sumcient time to separate into a top layer of gases containing HCl, an upper liquid layer of reaction product consisting mainly of isobutane and unconverted n-butane and substantially free from catalyst, and a lower liquid layer of catalyst containing substantial amounts of reaction product including unconverted n-butane. The gases at the top are vented through a line l2 controlled by a pressure regulating valve i3. Reaction product substantially free from catalyst'is removed from separator I0 through a line It and cooler l5. Catalyst is pumped through a line I6 by a pump I! and the major part thereof passes through The temperature of the reactants is minor part or the separated catalyst is passed through a valved line ll to a separating vessel which may be, as shown, considerably smaller in size than separator IO and which is provided with a cone-shaped bottom 2i. In separator 20 the catalyst-reaction product mixture is allowed sufllcient time to separate substantially completely into a lower liquid layer of catalyst and an upper liquid layer oi reaction product Any scribed, along with anhydrous aluminum chloride, which is introduced through a line 68 and the mixture is stirred and heated in vessel I4 to 150 to 250 F. by means not shown for a time and in amounts sumcient to produce a liquid catalyst containing not less than about 50 per cent by weight of aluminum chloride. This catalyst, after separation by suitable means (not 4 shown) of excess aluminum chloride or hydrogases in separator 20 are withdrawn and passed through a line 22 to line l2 and thus are removed from the system. Catalyst is pumpedfrom the bottom of separator 20 through a line 23 by a pump, either to waste or for such utilization as may be desired. Reaction product substantially free from catalyst is removed from separator 20 and passed through a line 25 into line l4 where it mixes with the major part of the reaction product separated in separator i0. Caustic soda solution is introduced through a line 26 into line l4 an'd the combined reaction prodduct and caustic soda solution are mixed in a mixer 21 and passed through a line 28 to a separating vessel 30 wherein a lower layer of caustic soda solution and an upper layer of washed, neutralized reaction product are formed. Used caustic soda solution is withdrawn from separator 30 and recycled through line 28 by a pump 32 to line i4 and thus back into mixer 21. Fresh caustic soda solution is introduced into and used caustic soda solution is removed from line 28 through the lines 32 and 34, respectively.

Washed, neutralized reaction product is withdrawn from separating vessel 30 through a line 35 controlled by a pressure regulating valve 35 and introduced into a holding vessel 31. From holding vessel 31 the reaction product is pumped through a line by a pump 4| into a fractionating column 42 where the mixture is tractionated into anoverhead of isobutane and propane and a bottoms of n-butane and pentane, the latter being chiefly iso-pentane. The n-butanepentane bottoms is pumped through a line 43 by a pump 44. Part of the n-butane-pentane bottoms thus removedis recycled through valved line 45 to line 2 and thus back into reaction vessel 5, while the remaining part of the n-butanepentane bottoms is caused to pass through a valved line into a fractlonating column ii. The isobutane-propane overhead from column 42 is pumped through a line 52 by a pump 53 to a fractionating column 54.

In fractionating column ii the mixture introduced thereinto is fractionated into an overhead of n-butane and a bottoms of pentanes, principally iso-pentane, while in fractionating column 54 the mixture introduced thereinto is fractionated into an overhead of propane and a bottoms of isobutane. The n-butane overhead of fractionating column 5| is pumped through a line 55by a pump 56 into line 45 and thus back into reaction vessel 5, while the pentane bottoms of fractionating column Si is pumped through a line 50 by a p p 6!. toms may be removed from the system through a valved line 62 but part at least is' passed through a valved line 53 into a catalyst mixing vessel 54. Alkylate bottoms such as that left as residue after distilling of! gasoline boiling range hydrocarbons from the alkylation productof a paraflin and an olefin may also be introduced through a line 65.

Pentane bottoms, with or without added alkylate bottoms, is introduced into Vessel 64 as de- Part of the pentane botcarbons, if any, is pumped through a line 61 by a pump 88 into line I and thus into reaction vessel 5;

The propane overhead of fractionating column 54 is removed from the system through a line 10, while the isobutane bottoms of this column is removed from the system through a line H for suitable use, e. g. for alkylating oleflns as described below in connection with Fig. 2.

In operating the system described above with reference to Fig. l of the drawings, the production 01 catalyst in vessel 64 and the removal of catalyst through line 23 are so co-ordinated that a constant amount of active catalyst is maintained in the. system, and this is most advantageously and economically accomplished by so conducting the isomerization in vessel 5 and so regulating the fractionating system represented by columns 42, II and 54 that the amount of pentane bottoms pumped from column 5| into catalyst mixing vessel 64 is suflicient, together with the necessary aluminum chloride, to produce all of the necessary catalyst.

The pressure in the system included within vessels 5, I0, 20, 21 and 30 is maintained at the desired constant level by means of regulating valve Band 36.

Referring to Fig. 2, isobutane contained in a storage vessel la and an olefin such as ethylene, propylene, butylene, or a mixture of such oleflns contained in a storage vessel lb are pumped through thelines 2a and 2b by the pumps 4a. and 41), respectively, into a line 2 and through a heat exchanger 3 into a reaction vessel 5, which is advantageously of the same design as described in connection with Fig. 1.

Minor amounts of HCl are introduced through a line 5 into line 2 and thus into reaction vessel 5. A liquid aluminum chloride-hydrocarbon catalyst, part of which is recycled catalyst and part of which is prepared as described below, is introduced into reaction vessel 5 through a line I and the catalyst, isobutane, olefin and 1101 are intimately contacted with each other in reaction vessel 5 at a suitable constant reaction temperature and under a constant pressure suflficient'to maintain the hydrocarbons in liquid state, thereby causing rapid alkylation of isobutane by olefin. The temperature of the reactants is maintained constant by continuously removing any heat liberated by the reaction, or by supplying heat if necessary. Heating or cooling coils may be used for this purpose. A mixture of catalyst and reaction product, including unreacted isobutane and HCl, is withdrawn from reaction vessel 5 through a line 8 and introduced into a separating vessel l0 provided with a cone-shaped bottom II. In separator III the mixture is allowed suflicient time to separate into a top layer of gases containing HCl, an upper liquid layer of reaction product consisting mainly of normally liquid viso-parafiinic hydrocarbons and unreacted isobutane substantially free from catalyst, and a lower liquid layer of catalyst containing substantial amounts of reaction product including 'unreacted isobutane. The gases at the top are vented through a line l2 controlled by a pressure regulating valve l8. Reaction product substantially free from catalyst is removed .from separator l8 through a line I4 and cooler l 5. Catalyst is pumped through a line l6 by a pump." and the major part thereof is passed through valved line I back into reaction vessel 6. A minor part or the separated catalyst is passed through a valved line l8 to a separating vessel 28 which may be, as shown, considerably smaller in size than separator l8 and which is provided witha cone-shaped bottom 2|. In separator 28 the catalyst-reaction product mixture is allowed suflicient time to separate substantially completely into a lower liquid layer of catalyst and an upper liquid layer of reaction product. Any gases in separator 28 are withdrawn and passed through a line 22 to line l2 and thus are removed !rom the system. Catalyst is pumped from the bottom of separator 28 through a line 28 by a pump 24, either to waste or for such utilization as may be desired. Reaction product substantially free from catalyst is removed from separator 28 and passed through a line 25 into line 14 where it mixes with the major part of the reaction product separated in separator i8.

. Caustic soda solution is introduced through a line 26 into line H and the combined reaction product and caustic soda solution are mixed in o a mixer 21 and passed through a line 28 to a sepa rating vessel 88 wherein a-lower layer of caustic soda solution and an upper layer of washed, neutralized reaction product are formed. Used caustic soda solution is withdrawn from separator I8 andrecycied through line 26 by a pump 82 to line l4 and thus back into mixer 21. Fresh caustic soda solution is introduced into and used caustic soda solution is removed from line 26 through the lines 38 and 84, respectively.

Washed, neutralized reaction product is withdrawn from separator 38 through a line 35 controlled by a pressure regulating valve 86 and is introduced into a holding vessel 31. From holding vessel 81 the reaction product is pumped through a line 48 by a pump 4| into a fractionating column 15. In fractionating column IS the mixture introduced thereinto is fractionated into an overhead of isobutane and a bottoms of deisobutanized alkylation product. The isobutane overhead is recycled through a line I6 by a pump 11 to line 2a and thus back to reaction vessel 6. The de-isobutanized alkylate bottoms of column I is pumped through a line 16 by a pump 19 to-a fractionating column 88 wherein the mixture is fractionated into an overhead of n-butane and a bottoms of completely de-butanized alkylate. The n-butane overhead is removed from the system through a line 8| and the de-butanized alkylate bottoms is pumped through a line 82 by a pump 83 into a fractionating column 84. In column 84 the mixture introduced thereinto is fractionated into an overhead or light alkylation product and a bottoms of heavier alkylate. ,The light alkylate overhead is withdrawn from the system thtrough a valved line 85 and may be used as, or as a constituent of, high octane number aviation fuel. The heavier alkylate bottoms may be withdrawn from the system through a valved line 86.

A part or all or the heavier alkylate bottoms valved line 92 to line 88 and thus to catalyst mixing-vessel 64.

Alkylateoverhead or bottoms, or both, are

introduced into vessel 64 as described above along with anhydrous aluminum chloride, which is introduced through a line 66, and the mixture is stirred and heated as described in the aforesaid copending applications to to 250 F. in vessel 64 by means not shown for a time and in amounts sufllcient to produce a liquid catalyst containing not less than about 50 per cent by weight oi aluminum chloride. This catalyst, after separation by suitable means (not shown) of excess aluminum chloride or hydrocarbon, it any, is pumped through a line 61 by a pump 68 into line 1 and thus into reaction vessel 6.

In operating the system described above with reference to Fig. 2 of the drawings, the production of catalyst in vessel 64 and removal of catalyst through line 23 are so coordinated that a constant amount of active catalyst is maintained in the system, and this is most advantageously and economically accomplished by so conducting the alkylation in vessel 6 and so regulating the fractionating system represented by columns 16. 88 and 84 that at least enough heavy alkylate bottoms is produced and pumped to vessel 64 to V produce the necessary catalyst.

The pressure in the system included within vessels 5, I8, 28, 21 and 88 is maintained at the desired constant level by means of regulating valves I3 and 86.

This invention has been described with particular reference to certain specific embodiments and examples but it is not limited to such specific embodiments and examples except as defined in the appended claims.

What I claim is:

l. A method of rapidly conducting the conversion or paraflin hydrocarbons into other, branched-chain paraflln hydrocarbons in the liquid phase and in the presence of a liquid aluminum halide-hydrocarbon catalyst, which comprises so thoroughly and intimately contacting the hydrocarbon reactant material with the catalyst that a mixture is produced which has substantially no tendency to separate in the zone of reaction and which separates slowly by gravity separation after withdrawal from the zone of reaction, withdrawing such mixture from the zone of reaction and introducing it into a first separating vessel and separating the mixture therein into a liquid layer comprising the major part of the reaction product substantially free from catalyst and a liquid layer comprising catalyst containing a substantial amount of reaction product, separately withdrawing the substantially catalyst-free reaction product and the reaction product catalyst mixture from said vessel, recycling the major part of the withdrawn reaction product catalyst mixture to the zone of reaction, introducing a minor part-ot the withdrawn reaction product catalyst mixture into a second separating vessel and therein efiecting a substantially complete separation of catalyst and reaction product, and separately withdrawing the substantially catalyst free reaction product and the thus separated catalyst from said second separating vessel.

2. The method of claim 1, wherein the sap arationsof catalyst from reaction product are by gravity separation.

3. A method of rapidly and uniformly conducting the conversion of paraflin hydrocarbons into other, branched-chain paraflin hydrocarbons in the liquid phase and in the presence or a liquid aluminum halide-hydrocarbon catalyst, which comprises so thoroughly and intimately contacting the hydrocarbon reactant material with the catalyst that a mixture is produced which has substantially no tendency to separate in the zone of reaction and which separates slowly by gravity separation after withdrawal from the zone of reaction, maintaining in said zone oi. reaction substantially constant temperature and pressure, withdrawing said mixture into' a first separating vessel and separating the mixture therein into a liquid layer comprising the major part of the reaction product substantially free from catalyst and a liquid layer comprising catalyst containing a substantial amount of reaction product, separately withdrawing the substantially catalyst-free reaction product and the reaction product catalyst mixture from said vessel, recycling the major part of the withdrawn reaction product catalyst mixture to the zone of reaction, introducing a minor part of the withdrawn reaction product catalyst mixture into a second separating vessel and therein efiecting a substantially complete separation of catalyst and reaction product, and separately withdrawing the substantially catalyst-free reaction product and the thus separated catalyst from said second separating vessel.

4. The method or claim 3, wherein the separations or catalyst from reaction product are by gravity separation.

5. A method of rapidly conducting the isomerization of paraflln hydrocarbons in the liquid phase and in the presence of a liquid aluminum halide-hydrocarbon catalyst, which comprises so thoroughly and intimately contacting the reactant paraflln with the catalyst that a mixture is produced which has substantially notendency to separate in the zone of reaction and which separates slowly by gravity separation after withdrawal from the zone of reaction, withdrawing such mixture from the zone of reaction and introducing. it into a first separating vessel and separating the mixture therein into a liquid layer comprising the major part the reaction product substantially free from catalyst and a liquid layer comprising catalyst containing a substantial amount of reaction product, separately withdrawing the substantially catalyst-free reaction product and the reaction product catalyst mix-- ture from said vessel, recycling the major part of the withdrawn reaction product catalyst mixture to the zone of reaction, introducing a minor part of the withdrawn reaction product catalyst mixture into a second separating vessel and therein effecting a substantially complete separation of catalyst and reaction product, and separately withdrawing the substantially catalyst-free reaction product and the thus separated catalyst from said second separating vessel.

6. A method of rapidly and uniformly conducting the isomerization o! parafiln hydrocarbons in the liquid phase and in the presence of a liquid aluminum chloride-hydrocarbon catalyst, which .comprises so thoroughly and intimately contactin'g the reactant parafiln with the catalyst that a mixture is produced which has substantially no tendency to separate in the zone of reaction and which separates slowly by gravity separation after withdrawal from the zone of reaction, maintaining in said zone of reaction substantially constant temperature and pressure, withdrawing from the zone or reaction and introducing it.

said mixture irom the zone of reaction and introducing it into a separating vessel 0! relatively, large size and separating-the mixture therein by gravity separation into a liquid layer comprising the major part of the reaction product substantially free from catalyst and a liquid layer comprising catalyst containing a substantial amount of reaction product, separately withdrawing the substantially catalyst-free reaction product and the reaction product catalyst mixture from said vessel, recycling the major part of the withdrawn reaction product catalyst mixture to the zone of reaction, introducing a minor part oi the withdrawn reaction product catalyst mixture into a separating vessel of relatively small size and therein eiiecting a substantially complete gravity separation of catalyst and reaction product, and separately withdrawing the substantially catalyst-iree reaction product and the thus separated catalyst i'rom said separating vessel of relatively small size.

7. A method of rapidly conducting the alkylation of paraflins with olefins in the liquid phase and in the presence of a liquid aluminum halidehydrocarbon catalyst, which comprises so thoroughly and intimately contacting a liquid mix,-

ture of a paraflln and an olefin with the catalyst that a mixture is produced which has substantially no tendency to separate in the zone of reaction and which separates slowly by gravity separation after withdrawal from the zone of reaction, withdrawing such mixture from the zone of reaction and introducing it into a first separating vessel and separating the mixture therein into a liquid layer comprising the major part of the reaction product substantially free from catalyst and a liquid layer comprising catalyst containing a substantial amount of reaction product, separately withdrawing the substantially catalyst-free reaction product and the reaction product catalyst mixture irom said vessel, recycling the major part of the withdrawn reaction product catalyst mixture to the zone of reaction, introducing a minor part of the withdrawn reaction product catalyst mixture into a second separating 'vessel and therein effecting a substantially complete separation of catalyst and reaction product, and separately withdrawing the substantially catalyst-free reaction product and the thus separated catalyst from said second separating vessel.

8. A method or rapidly and uniformly conducting the alkylation of paraifins with olefins in the liquid phase and in the presence of a liquid aluminum chloride-hydrocarbon catalyst, which comprises so thoroughly and intimately contacting a liquid mixture of a parafiln and an olefin with the catalyst that a mixture is produced which has substantially no tendency to separate in the zone of reaction and which separates slowly by gravity separation after withdrawal from the zone of reaction, maintaining in said zone of reaction constant temperature and pressure, withdrawing said mixture from the zone of reaction and introducing itinto a separating vessel of relatively large size and separating the mixture therein by gravity separation into a liquid layer comprising the major part of the reaction product substantially free from catalyst and a liquid layer comprising catalyst containing a substantial amount of reaction product, separately withdrawwithdrawn reaction product catalyst mixture to the zone of reaction, introducing a minor part of the withdrawn reaction product catalyst mixture into a separating vessel of relatively small size and therein effecting a substantially complete gravity separation of catalyst and reaction prodnet, and withdrawing the substantially catalystiree reaction product and the thus separated catalyst from said separating vessel or relatively small size.

9. The method claim 6, wherein said reactant paramn is normal butane.

10. The method of claim 8, wherein said liquid mixture or a paraiiin and an olefin is a liquid mixture of isobutane and at least one olefin oi the group consisting of C: to C4 olefins.

11. A method of isomerizing normal parflins to isoparafilns, which comprises contacting a normal paraflin iced in liquid state with a liquid aluminum halide -hydrocarbon catalyst so thoroughly and intimately as to produce a mixture which has substantially no tendency to separate in the zone or reaction and which separates slowly by gravity separation after withdrawal from the zone of reaction, and maintaining in the zone of reaction a constant temperature and a time of contact sufiicient to produce rapid isomerization and to produce a substantial amount of isoparamn material of higher molecularweight than said normal paramn reed, withdrawing said mixture from the zone of reaction and separating from it by gravity separation the major part of the reaction product substantially free from catalyst and catalyst containing a substantial amount or reaction product, recycling the major part of the reaction product catalyst mixture to the zone of reaction, effecting a substantially complete gravity separation of a minor part of the reaction product catalyst mixture into catalyst and reaction product, discharging the thus completely separated portion or the catalyst from the system. iractionating' the separated substantially catalyst-free reaction product, separating a normal paraflin traction of the same molecular species as said normal paraiiln reed, an isoparaifin traction of the same molecular weight as said normal paraflin feed, and an isoparafiin fraction or higher molecular weight than said normal parafiln feed, recycling said normal paramn traction to the zone of reaction, and producing an amount of fresh catalyst substantially equal to the catalyst discharged from the system by heating an aluminum halide with at least a portion of said isoparaifin traction of weight.

12. The method oi. claim 11, wherein said normal parafiln feed is normal butane and said aluminum halide is aluminum chloride.

13. A method 01 alkylating paraifins with olefins, which comprises contacting a paramn-olefin feed in the liquid-state with a liquid aluminum halide-hydrocarbon catalyst so thoroughly and intimately as to produce a mixture which has substantially no tendency to separate in the zone 0! reaction and which separates slowly by gravity separation after withdrawal from the zone of reaction, and maintaining a temperature, a time of contact and a paraflin-olefin ratio in the zone of reaction suilicient to produce rapid alkyiation and to produce a substantial amount of Cs and higher isoparaflins, withdrawing said mixture from thezone or reaction and separating irom it by avity separation the maior part 01 the reaction product substantially free from catalyst and catalyst containing a substantial amount 0! reaction product, recycling the major part of the reaction product catalyst mixture to the zone of reaction, eflecting a substantially complete gravity separation 01 a minor part of the reaction product catalyst mixture into catalyst and reaction product, discharging the thus completely separated portion of the catalyst from the system, iractionating the separated substantially catalyst-tree reaction product, separating a paraifin fraction 01' the same molecular species as the paraflin in said parafiin-olefin feed, an isoparafilnic fraction consisting essentially of gasoline boiling range hydrocarbons, and a Ca and higher iso-paraflinic traction, recycling said paraflln fraction of the same molecular species to the zone of reaction, and producing an amount or fresh catalyst substantially equal to the catalyst dischrged from the system by heating an aluminum halide with at least a portion of said Go and higher iso-paraflinic fraction.

14. The method of claim 13, wherein said paraflln-olefln'ieed is composed principally of isobutane and at least one olefin oi the group consisting of C2 to C4 olefins, and said aluminum halide is aluminum chloride.

POVL OSTERGAARD.

higher' molecu lar 

